Heavy rain expected today and Friday has prompted a flash flood watch for most of central Pennsylvania.

“It looks like as we move into this afternoon and evening a steadier rain will start moving in and continue for most of the night and even into the day tomorrow,” according to meteorologist Elyse Colbert of the National Weather Service in State College.

An average of 1 1/2 to 2 1/2 inches of rain will fall, with locally higher amounts, she said.

“The rain will start moving out Friday evening and Saturday and Sunday look dry,” she said.

The flash flood watch runs from this evening through Friday evening.

“The showers and thunderstorms could produce some very heavy rainfall that could cause some fast rises in creeks and streams, especially the smaller ones that respond very quickly to rain,” Colbert said. “It could also cause some ponding of water on roads and flooding in poor drainage areas.”

Temperatures will be in the mid- to upper-70s today.

“One of the things causing the rain is a cold front moving through the area so it will be much cooler tomorrow with highs in the mid-60s. It will be a couple of degrees warmer Saturday and in the mid-60s on Sunday.

“It will definitely be a lot cooler than the mid-80s we were seeing a couple of days ago,” Colbert added.

The first half of next week the area will see cooler than normal temperatures, with highs in the mid- to upper-60s and around 70 on Tuesday.

“It will slowly warm up for the rest of next week, with temperatures where you would expect them for this time of year, in the mid- to upper-70s.

“After the system moves through this weekend, you will see a drier period,” according to Colbert.

There is a very slight chance Monday for a scattered shower or thunderstorm in the afternoon.

“Tuesday and Wednesday are definitely dry,” Colbert said. ‘It looks like a change in pattern. I think after the rain we will appreciate the break this weekend.”